Between August 23 and August 26, 2013 the San Francisco Department of Public Health (SFDPH) received eight reports of laboratory confirmed E. coli O157 infections in residents of San Francisco. Typically one case per month is reported in San Francisco. Public health investigators from SFDPH and the California Emerging Infections Program initiated an outbreak investigation and conducted a case-control study. Results showed that an outbreak of E. coli O157 occurred among patrons of Burma Superstar Restaurant. In total 22 confirmed and probable case patients were identified. A garlic noodle dish was strongly associated with illness, but the specific ingredient causing disease was not identified. An environmental investigation resulted in recommendations for the restaurant that included improved handwashing and food handling, as well as a requirement for Food Safety training among restaurant staff.